This invention relates generally to identification documents and a method for making such identification documents. More particularly, this invention relates to a security feature for such identification document and to a secure identification document that allows detecting a fraudulent modification of the existing official personalization or a completely falsified document.
Identification documents are associated with secure applications, such as for example driving licenses, identity cards, membership cards, badges or passes, passports, discount cards, banking cards, money cards, multi-application cards, and other papers of value; and security documents such as bank notes. Such documents are widely used, they may comprise an electronic module or not. If they comprise an electronic module, they can function either with contact and/or without contacts depending on the application to which they are intended. They may take the shape of card or a booklet or something else. Such identification documents are graphically personalized. Personalized information is personal data of the card's owner, i.e for example his photo, his name, his birth date, his social security number, his biometric information such as his fingerprint for example, a validity date, an identification number allocated to him etc. . . . . This personalized information is printed onto the surface of the document, or into one or more constitution layers of the document. Because of the value and importance associated with each of these data carriers, they are often the subject of unauthorized copying and alterations, and forgeries.
To prevent such activities from being carried out on these data carriers, different types of visual and touchable security features have been added to data carriers. One of these security features consists in printing UV fluorescent inks, by ink jet printing technology for example, for drawing a security pattern, which is not visible to naked eyes under daylight radiations, but which appears under UV radiations as a colored image and/or text because they fluoresce with visible light when illuminated with UV light. Such security feature using UV fluorescent inks is widely used now, but it is only used as a background printing, so that it is impossible to personalize it. Moreover, with inkjet printers, one can use fluorescent inks, in order to print for example facial image only visible under UV light making each document specific to the document holder. However, the number of colors/inks is limited and typically, only one UV ink can be used, its color being for example red, blue or yellow. Consequently, forgers can also obtain the same effect by using the same ink and a relatively low cost printer.
Considering the above, a problem intended to be solved by the invention, is to propose a process for securing an identification document by using UV sensitive ink(s) to define a pattern only visible under UV radiations, i.e. UV absorbing without absorbing also the visible radiations, said process being easy to implement, so that it does not involve over costs, and enabling to obtain an enhanced security feature, which achieves an effect that is impossible to reproduce in a simple manner.